switch gcc versions in debian

gistfile1.sh

#install new versions of gcc and g++
sudo apt-get install gcc-4.8 g++-4.8

#remove existing alternatives
sudo update-alternatives --remove-all gcc
sudo update-alternatives --remove-all g++

#add new and old version to update-alternatives db
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 40 --slave /usr/bin/g++ g++ /usr/bin/g++-4.8
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-8 40 --slave /usr/bin/g++ g++ /usr/bin/g++-8


#choose the needed version
sudo update-alternatives --config gcc